Flexible pressure-responsive diaphragm



Jan. 26, 1954 2,667,183

FLEXIBLE PRESSURE-RES PPPPPPPPPPPPPP GM nnnnnn or Jan. 26, 1954 R. s. EMERsoN 2,667,133

FLEXIBLE PRESSURE-RESPONSIVE DIAPHRAGM Filed Dec. 7, 1951 2 Sheets-Sheei'I 2 Inventor m-.mficu Sunni E nemou 14 Horn e y Patented Jan. 26, 1954 FLEXIBLE PRESSURE-RESPONSIVE DIAPHRAGM Reginald StanleyEmerson', London, England, as-

signor to D. Napier & Son Limited, London, England, a company of Great Britain Application December 7, 1951, Serial No. 260,348

Claims priority, application Great Britain January 3, 1951 NT OFFICE 3 Claims. 11

This invention reIates to flexible pressure-repressure range the law relatine the fiuid pressure sponsive diaphragms of the kind comprising an to the-force applied to the centre partfoffithe annular comparatively rigid rimportion, a comdiaphragm will be; aV substantially straight' line paratively rigid centralportion coaxial with'the laW. rim portion and of a diameter leaving an an- 5 To this end a f flexible diaphragmaccording nular space between the central and rim portO the present inVentiOn COmDriSeS a rigid' antions, and an annular intermediate flexible pornular rim 1101421011,H a rigid central --portioncontion permitting relative movement between the Centrie With but spaced from the rim-portion, rim and central portions, in a direction normal and an annular intermediate exible portion to the general plane of the diaphragm, for exextending between the rim and the central porample under the action of changes in the fiuid tions, Vthis intermediate flexible portion being pressure acting on the diaphragm. constituted by a series-of separateradiallyex- In one form of such diaphragmsas commonly tending SeOfiOnS Of rigid material spacedby formed, the annular rim portion and the central narrow annular gaps from the central'and `rim portion are formed as separate metal members portions, each section subtendingA a relatively and the annular intermediate fiexible portion Small angle at the centre ofthe diaphragm and is formed by a, discof. rubber `or similar imthe sections being-separated from one another pervious flexible material the outer circumferenby narrow slit-like radial gaps, and .impervious tial portion of which is clamped. or otherwise flexible sheet-material extending between and rigidly secured to the rim portion whileits inner making a fluid-tight-J'unCtiOn With the inner edge circumferential edge is ..similarly clamped or of the rim portion and the outerV edge of the otherwise rigidly secured to a face of the central central portion and lying in contact .with Vthe portion. In an alternativeform in commonuse radially extending sections so as to providev an the diaphragm is formed completely of thin impervious sealcovering the gaps between .the metal with circumferential` corrugations in its radially extending sections` andbetween lthese intermediate portion to render such portion exsections and the'rim-'and Vcentral portions. ible, while its rim .and central portions are lA diaphragrn according tO the invention is informed liat and usually clamped respectively tended to beusedin association with inner .and between parts between which the diaphragm outer parts betweenwhich it extends; theinner extends, circumferential edge of the outer partand the The known diaphragms .in :which the flexible outer circumferential edge of the inner part overannular portion is in the -form of a fiexible sheet lapping .toa smalll degree respectivelythe outer or rubber or the like, have the advantage that and inner endsof the individual. radially. exthe flexible portion has little or no inherent tending sections of. the intermediate portionof resilience and such :diaphragms therefore are the diaphragm: sov vthat such inner.. and l.outer sensitive to small pressure changes and can be parts constitutein effect fulcra .onwhich vthe used Where it is necessary or desirable that the ends of such radiall'y...extending` sectionsabear flexible part of the diaphragm itself should have and can pivot freely. little or no natural resilience. Such diaphragms Thus eachv radially extending section is supare, however, not vsuitable for use where the 40 ported at its. innerand. Outer. end respeotively diaphragm has to Withstand high fluid pressures, on the two. parts' .between Vwhich "theflexible while moreover the tendency for distortion or part of the diaphragm extends: and the pressure bulging of the fiexiblematerial to occur with Vacting on such flexible partof .the diaphragm-.is increases in pressure tends to make the law retransmitted directlyxto suchfparts through'.;the lating pressure changesV to. relative movement ends of the radially extending sections which between the rim-and central portions complex. themselves form asupport for :the sheet of im- The object off the present'invention is to'propervious. fiexiblezmaterial;.extending over. them vide an improved flexible diaphragm, primarily and ifilling the narrow'gaps Vbetweenl themand but 1101? eXCluSiVely'intended fOI' USB With pres- .between their ends and. .the ri1n, and .central sure-operated or pressure-responsive control portions of ,the .diaphragm. apparatus which willbe suitable for use with Preferably the .sheet of `.flexible materialV is comparatively highfluid pressures,l will have bonded to the inner edge of. .the rim portionand little or no inherent resiliencej as regards its to the outer edgeof the central portionand to annular flexible'. portion `within VAits operating the faces ofV the radially extending,..sections.of rangaand-:will 'alsof.-be. fsuchi that: over a wide the intermediatefportionV over whichoit extends,

'and in any case it will be understood that the diaphragm will be arranged so that the face thereof exposed to the higher pressure is that 'over which the impervious flexible material extends so that the fiuid pressure tends to assist rather than otherwise the close adherence of the fiexible material to the rigid parts of the diaphragm.

A diaphragm according to the invention may be manufactured in various ways, but according to a further feature of the invention a method of forming such a diaphragm comprises machining in one face of a plate an annular recess with concentric inner and outer grooves in the face of the recess lying adjacent to, but slightly spaced respectively from, the inner and outer circumferential edges of the recess, and also machining in such face a series of radial grooves extending beyond the edges of the recess and cutting into the base of the recess, then filling the recess and the grooves associated therewith with plastic material which is then bonded thereto and grinding or otherwise machining down the face of the plate remote from the recess to a point beyond the bases of the concentric inner and outer grooves in the base of the recess referred to.

One construction of diaphragm according to the invention and a method of manufacturing it will now be described with reference to the accompanying drawings, in which:

Figure 1 is a front elevation of the diaphragm, shown without the flexible material,

Figure 2 is a cross-section in a plane containing the axis of the diaphragm through an assembly in Which the diaphragm is used, and

Figure 3 is a cross-section in a plane, containing the axis of the diaphragm eventually produced, to illustrate the manner in which the diaphragm is made.

As shown in Figures 1 and 2, the diaphragm comprises a rigid annular rim portion A of metal having spaced holes Al therein, a rigid annular central portion B also of metal concentric with but spaced from the rim portion A, and an annular intermediate flexible portion extending between the rim A and the central portion B and spaced by narrow annular gaps C and Cl respectively from the central portion B and the rim portion A, this intermediate flexible portion being constituted by a series of separate radially extending metallic sections D each subtending a relatively small angle at the axis of the diaphragm and separated from one another by narrow slit-like radial gaps Dl, and impervious flexible sheet material E extending between and making a fiuid-tight junction with the inner edge of the rim portion A and the outer edge of the central portion B and lying in contact with and extending completely over the faces of the sections D on one side of the diaphragm and covering and extending into the gaps C, Cl and Dl. Tongues B1 are formed on the central portion B as shown.

When the diaphragm is incorporated in apparatus in which it is to be used the inner and outer ends of the sections D are arranged to rest upon abutments or fulcrum surfaces. Thus in the construction shown in Figure 2 the diaphragm is assembled between the two parts R and Rl of a casing with its rim portion A clamped between annular faces respectively on the two parts of the casing by bolts F passing through the two parts of the casing and through a ring G by which the outer circumferential part of a flexible diaphragm H of other type lis clamped to the rear face of the part Rl, while the central portion B of the diaphragm is clamped between clamping rings J, Jl on the end of an axially movable pin or control member or shaft K by means of a nut J2 engaging a screwthread on the end of the pin K and serving also to clamp the inner circumferential portion of the diaphragm H to the pin K by means of a clamping ring Hl. A Sealing ring L is provided to prevent leakage of fluid along the part of the pin surrounded by the clamping rings J, Jl and outwards between the faces of the ring J and central portion B of the diaphragm While a Sealing ring L1 provides a seal between the ring J and the pin K.

The tongues B1 engage longitudinal grooves Kl in the pin K as shown, to prevent rotation of the portion B of the diaphragm during assembly on the pin K. g

As shown the ring J is provided with an inclined surface M on which the inner ends of the sections D rest and can pivot so that this surface forms a fulcrum for each of these inner ends while the part Rl of the casing is provided with an inclined surface N which similarly acts as a fulcrum for the outer ends of the sections D. Each section D is thus pivotally supported on the frusto-conically shaped fulcrum surfaces M and N at its ends.

In the construction shown the diaphragm according to the invention lies between a high pressure chamber IO and a low pressure chamber P and it will be seen that pressure acting on the diaphragm is thus transmitted'by the sections D directly to the part Rl of the casing through the fulcrum surface N and to the pin K through the fulcrum surface M, and that the sheet of impervious flexible material E is supported by the sections D except for the parts in the narrow radial gaps Dl which, by reason of their limited area and substantial support from the surrounding parts, are Well capable of withstanding high pressures.

The method of construction of a diaphragm according to the invention diagrammatically illustrated in Figure 3 is as follows: A circular metal plate Q of substantial thickness with a central hole Q1 is machined in the manner indicated so as to provide in one face an annular recess Q2 of a depth (a) with concentric inner and outer grooves Q3, Q*l formed in the base of this recess and having a total depth (b) measured from the adjacent face of the plate Q, these grooves being as shown slightly displaced respectively from the inner and outer circumferential edges of the recess Q2. Also formed by machining in the same face of the plate Q is a series of radial grooves Q5 of part-cylindrical form with a depth slightly exceeding that of the grooves Q3 and Q'* and a length measured radially of the plate Q such as to extend beyond the inner and outer circumferential edges of the recess Q2. When the plate Q has been machined in the manner indicated the recess Q2 and the grooves Q3, Ql, Q5 associated with it are filled with plastic material of a kind Which, after curing, will be of an impervious flexible nature, for example a Synthetic rubber, and this material is then cured and during the curing bonded to the plate Q. The face of the plate Q containing the recesses Qz, Q3, Q'l, Q5, now fllled with impervious flexible material, and this flexible material is then machined down as by grinding so as to reduce the thickness of the plate Q as a whole to the dimension indicated at (c), following which the opposite face of the plate Q is machined down as by turning to the dimension (d) and then by grinding to the dimension (e), when it will be seen that the part of the plate Q between the grooves QS and Q4 will have been separated into a series of separate sections divided from one another by the narrow slots Dl represented by the grooves Qfi and bounded at their ends by the slots C and Cl represented by the grooves Q3 and @4, while the impervious flexible material Will extend over the inner circumferential edge portion of the outer part A of the plate now represented by the part of the plate outside the groove Q4 and over the outer circumferential portion of the central part of the plate now represented by the part of plate inside the groove @3.

In one particular example the plate Q may initially be, say, 3 inches in diameter and 1 inch thick and have a central hole Ql of 1/2 inch diameter, the recess Qz may have a depth of 0.3 inch, an external diameter of linches and an internal diameter of, say, inches, each of the grooves Q3, Q4 having a width of, say lbr of an inch and a depth measured from the adjacent face of the plate Q of, say, .06 inch, the mean diameter of the groove Qti being l-- of an inch while the mean diameter of the inner groove is of an inch, the width of each slot Q5 being, say, 1/(54c of an inch while the final thickness of the plate after both faces have been ground is, say, about .04 inch with the final thickness of the plastic material on the sections D say .022 inch.

What I claim as my invention and desire to secure by Letters Patent is:

1. A flexible diaphragm comprising a rigid annular rim portion, a rigid central portion concentric with but spaced from the rim portion, and an annular intermediate fiexible portion extending 'between the rim and the central portions, this intermediate fiexible portion being constituted by a series of separate radially extending sections of rigid material, spaccd by narrow annular gaps from the central and rim portions, each section sub-tending a relatively small angle at the centre of the diaphragm and the sections being separated from one another by narrow slit-like radial gaps, and impervious flexible sheet material extending between and making a fiuid-tight Junction with the inner edge of the rim portion and the outer edge of the central portion and lying in contact With the radially extending sections so as to provide an impervious seal covering and extending into the gaps between the radially extending sections and between these sections and the rim and central portions, said impervious flexible material being bonded to the parts over which it extends.

2. Fluid pressure responsive apparatus comprisin r a high pressure and a low pressure chamber, a fiexi'ble diaphragm extending and constituting a dividing wall between the high pressure and low pressure chambers and comprising a rigid annular rim portion, a rigid central portion concentric with but spaced from the rim portion, and an annular intermediate flexible portion ext ending between the rim and central portions, this intermediate flexible |portion being Constituted by' a series of separate radially extending sec-tions of rigid material spaced by narrow annular from the central and rim portions, each section subtending a relatively small angle at the centre of the diaphragm and the sections being separated from one another by narrow slitlike radial gaps, and impervious flexible sheet material extending between and making a fluid tight junction with the inner edge of the rim portien and the outer edge of the central portion and lying in contact with the faces of the radially extending sections adjacent to the high pressure chamber so as to provide an impervious seal covoring and extending into the gaps between the radially extending sections and between these sections and the rim and centra1 portions, said flexible impervious material being bonded to the parts over which it extends, a control member connected to the central portion, and annular fulcrum surfaces in the low pressure chamber and respectivelj rigid with the walls of the chamber and the control member on which fulcruin surfaces can rest and pivot respectively the outer and inner ends of the radially extending sections.

3. Fluid pressure responsive apparatus as claimed in claim 2 in which the annular fulcrum surfaces are frusto-conical.

REGINALD STANLEY EMERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,466,243 Neal Aug. 28, 1923 2,275,712 Zand Mar. 10, 1942 2,554,008 Burger May 22, 1951 FGREIGN PATENTS Number Country Date 297,216 Great Britain Sept. 20, 1928 

